Those who deal with ruqyah (incantation) as prescribed in Islam have mentioned some of the symptoms from which it may be known whether a person has been possessed by the jinn or affected by the evil eye. They are not definitive symptoms and may vary in some cases, and may be more or less in other cases.
As for the symptoms of possession, they are:
1. Turning away and reacting strongly when hearing the adhaan (call to prayer) or Quran
2. Fainting, seizures and falling when Quran is read over him
3. A lot of disturbing dreams
4. Being alone, keeping away from people and behaving strangely
5. The devil who is dwelling in him may speak when Quran is recited over him.
As for the symptoms of being affected by the evil eye, Shaykh ‘Abd al-‘Azeez al-Sadhan (may Allah preserve him) said:
If it is not a real sickness, then the symptoms may take the following forms:
Headaches that move from one part of the head to another; yellow pallor in the face; sweating and urinating a great deal; weak appetite; tingling, heat or cold in the limbs; palpitations in the heart; pain in the lower back and shoulders; sadness and anxiety; sleeplessness at night; strong reactions due to abnormal fears; a lot of burping, yawning and sighing; withdrawal and love of solitude; apathy and laziness; a tendency to sleep; health problems with no known medical cause.
These signs or some of them may be present according to the strength of the evil eye or the number of people who put the evil eye on others. End quote. Al-Ruqyah al-Shar’iyyah.
And Allah knows best.